This invention relates to an improved construction for an internal combustion engine and more particularly to an improved construction for a wet sleeve insert in a cylinder block for an internal combustion engine.
In large internal combustion engines, typically an engine cylinder block is fitted with cylinder sleeves that project into bores cut into the block. The sleeves are usually sealed at opposite ends to the block. An open volume or passage is defined around the sleeve intermediate the ends for flow of coolant. When such an engine is operating, the differential expansion of the block relative to the sleeve, the flow of coolant about the sleeve, the vibration of the engine and other factors may cause electrolytic pitting of the outside surface of the cylinder sleeve in the coolant passage. This pitting may further cause cavitation of coolant as it flows about the sleeve which, in turn, may produce hot spots in the cylinder sleeve and general degradation of the operation of the engine.
Various suggestions have been made for elimination of electrolytic pitting of the outside surface of the sleeve. One such suggestion provides for boring a hole through the block adjacent each sleeve. A copper bolt or other conductor is then threaded through the block against the region of the sleeve which becomes pitted. The copper bolt acts as a conductor to alleviate the electrolytic pitting of the outside surface of the sleeve by conducting static electricity away from that surface.
While arrangement of a conductive rod from the sleeve to the engine block has proven to be useful, it does become time consuming and expensive to modify or adapt each cylinder in an engine block with such a conductor. The present invention contemplates an improved construction for elimination of pitting due to electrolytic action.